From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272877AbTHERF4 (ORCPT ); Tue, 5 Aug 2003 13:05:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272553AbTHERDT (ORCPT ); Tue, 5 Aug 2003 13:03:19 -0400 Received: from tux.rsn.bth.se ([194.47.143.135]:5517 "EHLO tux.rsn.bth.se") by vger.kernel.org with ESMTP id S272949AbTHERAO (ORCPT ); Tue, 5 Aug 2003 13:00:14 -0400 Subject: Re: [PATCH] O11int for interactivity From: Martin Josefsson To: Andrew Morton Cc: Valdis.Kletnieks@vt.edu, piggin@cyberone.com.au, wli@holomorphy.com, kernel@kolivas.org, linux-kernel@vger.kernel.org In-Reply-To: <20030804225532.494bfd31.akpm@osdl.org> References: <200307301038.49869.kernel@kolivas.org> <20030802225513.GE32488@holomorphy.com> <200308030119.47474.m.c.p@wolk-project.de> <200308042106.51676.m.c.p@wolk-project.de> <20030804195335.GK32488@holomorphy.com> <3F2F00B0.9050804@cyberone.com.au> <20030805024103.GM32488@holomorphy.com> <3F2F1F80.7060207@cyberone.com.au> <20030805031341.GN32488@holomorphy.com> <3F2F231C.3030901@cyberone.com.au> <20030805033119.GO32488@holomorphy.com> <3F2F26BA.3060904@cyberone.com.au> <200308050454.h754sBqM004950@turing-police.cc.vt.edu> <20030804225532.494bfd31.akpm@osdl.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1060102809.3174.15.camel@tux.rsn.bth.se> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.0 Date: 05 Aug 2003 19:00:09 +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2003-08-05 at 07:55, Andrew Morton wrote: > Another possibility is that xmms is getting stuck in a read. The > anticipatory scheduler is currently rather tuned for throughput. Judging > by the vmstat trace which was posted, we have a classic > read-stream-vs-write-stream going on. We trade off latency versus > throughput; perhaps wrongly. You can decrease latency (at the expense of > throughput) by decreasing the settings in /sys/block/hda/queue/iosched. > > To a point, it is a nice linear tradeoff, and someone should put the time > in to tweak and characterise it. I believe it was my trace wli posted. No swapping was going on, swappiness set to 30 X was quite jerky and uninteractive during this and sometimes it froze for up to 5 seconds (the sound usually stopped during the freezing). Since there wasn't any swapping going on and quite a lot of cpu left we either have quite some latency when reading back parts of X that previously got discarded or massive stalls in kernelspace somewhere. One thing I noticed was that when evolution started checking for new mail in a lot of folders I get a lot of seeks and the throughput naturally decreased but X got really responsive again. This points away from X beeing discarded and read back in from disk since that would take some time with all those seeks as well. The machine this was tested on is a pIII 700 with 704MB ram and IDE disks (everything was against the same disk) -- /Martin